Highway crossing signaling system



Jan. 25, 1938. o. s. FIELD ET AL 2,196,682

HIGHWAY CROSSING SIGIIALIIIIN'G' SYSTEM Filed Feb. 29. 1956 INVENTORS w Zl/ ATTORN'EY wig i Patented Jan. 25, 1938 UNITED STATES FATE OFFICE HIGHWAY CROSSING SIGNALING SYSTEM Application February 29, 1936, Serial No. 66,422

6 Claims.

This invention relates in general to signaling systems, and more particularly to apparatus for the control of highway crossing signals, which invention is of later origin than the invention disclosed in the earlier filed application of Mackey Ser. No. 66,232 filed February 28, 1936 and the later filed application of Reichard Ser. No. 74,924 filed April 1'7, 1935, and no claim is made herein to anything disclosed in said Mackey and Reichard. 19 applications.

It is customary to control highway crossing signals in a manner to provide a danger warning to highway trafiic when a train reaches a point at a fixed distance from the highway, which dis tance is suificient to provide the required Warning time when traversed by a maximum speed train. However, when the same distance is traversed by a slow speed train, the warning time becomes so excessive that the efiectiveness of the signal to protect highway traffic is reduced and it may even be erroneously disregarded. For a similar reason, it is not desirable to continue a warning highway signal indication when a train stops within the signal controlling distance and is not about to cross the highway.

In View of the above and other considerations, it is proposed in accordance with the present invention to provide a means controlled by a train approaching the highway for operating a highway 30 warning signal for substantially the same length of time prior to the actual arrival of the train at the highway regardless of the speed of the train.

It is further proposed to provide means for discontinuing operation of a highway warning indi- 35 cation after a predetermined time in the event a train does not continue toward the highway and. for again starting the warning when the train proceeds to cross the highway.

Other objects, purposes and characteristic features of the present invention will be apparent as the description thereof progresses, during which references will be made to the accompanying drawing which shows in a simplified. and diagrammatic manner one specific embodiment of the 45 present invention.

In the accompanying drawing, a portion of railway track having an indicated normal direction of trafiic from left to right is illustrated a crossing a highway represented by H, the track being divided by insulating joints in the usual manner into track sections 2 and 3 which are traversed sequentially by a train approaching the highway. A track circuit as provided for each track section which includes the usual track relay T (with corresponding exponent) and the usual track battery B (also with corresponding exponent).

Any type of highway crossing signal may be employed in the present system such as flashing light signals, bells, crossing gates or the like, but 5 for simplicity'a highway signal has been illustrated merely as an incandescent lamp HG. The signal HG is controlled by a control relay CG which is normally energized over a circuit from the terminal of a suitable source of line circuit energy, through front contact 6 of track relay T front contact 7 of track relay T through the windings of relay CG, to The signal control relay CG is also under the joint control of the timing apparatus of the present system, and the control relay CG when energized as shown holds the highway signal HG in an inoperative or deenergized condition at its open back contact 8.

The timing apparatus illustrated diagrammatically in the accompanying drawing is operable by a reversible motor M of any suitable type having constant speed characteristics. The motor Mmay be energized from any suitable source of energy but for convenience is shown as energized from a split potential battery illustrated as battery BX and BY, and this motor M may be provided with a permanent magnet field or an electromagnet field energized with a fixed direction of current in the usual manner. The armature of motor 2 M is directly connected to a shaft ill which drives a low speed shaft l2 through suitable reduction gears represented by a helical gear I3 on shaft l driving a ring gear M on shaft l2.

A means is provided for checking rotation of the parts of the present timing means which is illustrated conventionally as a centrifugal device D comprising an upper collar l6 fixed to shaft l0 and connected by the usual centrifugal actuating arrangement to a lower collar l'l slidable longi- 40 tudinally on shaft Iii. A compression spring l8 between collars l5 and I! normally biases the lower collar I! to its illustrated lower position wherein an insulated contact disc 20 is disengaged from upper fixed contacts represented diagranimatically in the-drawing. This centrifugal device D obviously operates to raise the contact disc 20 into engagement with its fixed contacts when the shaft I0 is operated at a normal speed in either direction. V V

A cam 22 is provided on the low speed shaft l2 which is provided with a lobe as shown for opening a circuit through either contacts 23 or 24 after the shaft l2 has moved through slightly less than one-half a revolution in either direction from its illustrated position. This cam 22 is employed to prevent undue rotation of the shaft E2 in either direction by opening the energizing circuit for motor M as will be later described.

Three contacting drums 26, 2? and 28 are also provided on shaft I2, the drums 26 and 21 being employed in restoring the shaft I2 to its normal illustrated position after operation of the apparatus. These drums 26 and 2'! may be of insulating material with opposite arranged sectors of conducting material 3!! and 35 respectively, the sector 30 being arranged to electrically connect wiping contacts 3! and 32 when shaft I2 is rotated in a counter-clockwise direction from its illustrated position, and in a similar manner the sector 34 is arranged to electrically connect Wiping contacts 35 and 36 when shaft I2 is rotated in a clockwise direction from its illustrated position.

The drum 28 which may also be of insulating material is provided with a sector 31 cooperating with lower wiping contacts 38 and 39 which are preferably adjustably mounted. These contacts 38 and 39 are employed in controlling the secondary energizing circuit for signal control relay CG as will be later described, and similar upper contacts 40 and 4| also cooperating with sector 31 are employed in combination with a cutout relay ii for discontinuing operation of the highway warning. The cutout relay I] is provided to prevent undue withholding of the highway warning in the event some abnormal condition retains drum 28 in a position closing contacts iii-AI after a train movement has been completed, as will be later described.

It is believed that the operation of the present apparatus can best be described by assuming certain values which of course will be actually determined in accordance with the requirements of each particular application. For example, it will be assumed that the required highway warning time prior to the arrival of a train is 20 seconds, and that the maximum speed of trains approaching the highway H is 90 miles per hour. In accordance with the above values, it will then be assumed that section I is 2640 feet in length, section 2 is 2200 feet, and section 3 is 440 feet, that is, section I is equal to the combined lengths of sections 2 and 3.

A train upon entering section I drops relay T and energizes motor M with a normal direction of current over a circuit from the terminal of battery BY, through motor M, front contact of relay T back contact 45 of relay T and through cutout contact 23 to the terminal of battery BY. However, when a train traverses section I and enters section 2, relay T drops and reverses the direction of current in motor M, which direction of current may be traced from the terminal of battery BX, through cutout contact 24, back contact 45 of relay T through motor M to the terminal of battery BX.

The normal direction of current supplied to motor M while section I is occupied causes a rotation of shaft I2 in a clockwise direction, and the gears I3I I are so arranged in accordance with the speed of motor M that the lower end of the shunting sector 3'! of drum 28 is moved in a clockwise direction to a position which just closes contacts 3839 after the motor M has operated for a period of 20 seconds.

Considering that a train enters section I at the maximum speed of 90 miles per hour, it will be clear that such a train traverses the length of section I, which is 2640 feet,'in exactly 20 seconds,

and consequently the entrance of this train into section 2 reverses the direction of rotation of drum 28 just as contacts 3839 are about to close. This high speed train upon entering section 2 drops relay '1 and opens the energizing circuit for relay CG at front contact 6, and as contacts 3839 are open, relay CG will drop and energize the warning signal through its back contact 8. In other words, a train traveling at a maximum speed of 90 miles per hour starts the highway warning upon entering section 2, and as the distance from this point to the highway is 2640 feet, this warning will be given for the required time of 20 seconds before this train reaches the highway.

Now considering that a train enters section I at a speed of miles per hour, this train consumes 30 seconds in traversing section I thereby rotating drum 28 in a clockwise direction for 30 seconds, the first 20 seconds of this rotation being required to close contacts 3839 and for the remaining 10 seconds the lower end of the shunting sector 3'! moves a proportional distance beyond contact39. Consequently as the speed of shaft I2 is the same in a counter clockwise direction as in a clockwise direction, contacts 3839 will remain closed for 10 seconds after the direction of rotation of motor M is reversed by this 60-mileper-hour train entering section 2.

With contacts 3s-as closed when a train enters section 2, relay CG is maintained energized over an auxiliary circuit from through contacts 3839, contact 29 of the centrifugal device D, front contact I of relay T through the windings of relay CG, to It will be clear that the drop ping of relay T opens the normal energizing circuit for relay CG at Contact 6 at the same time that the direction of rotation of motor M is being reversed, and consequently the contact 20 of the centrifugal device D opens momentarily until the full speed in the reverse direction is attained by motor M. Consequently the above auxiliary circuit will not be immediately closed when the normal circuit for relay CG is opened, but the armature of relay CG is suificiently slow releasing as illustrated to prevent it from momentarily dropping at this time.

In this manner, the highway warning signal is not energized until 10 seconds after this GO-mileper-hour train enters section 2, but after this period of 10 seconds, the sector 3'! will have rotated in a counter clockwise direction to a point opening contacts 3839 to deenergize relay CG and start the highway warning. Inasmuch as the 60-rnile-per-h0ur train traverses the distance from the entrance end of section 2 to the highway, which is 2640 feet, in 30 seconds, this 10 second delay before starting the warning results in a warning time of 20 seconds, the same as provided by the -mile-per-hour train.

Now considering that a train enters section I traveling at a slow speed of 15 miles per hour thus consuming 120 seconds in traversing section I, during which time drum 28 is rotated in a clockwise direction so that contacts 38-39 are closed for seconds before this slow speed train enters section 2 to reverse the direction of rotation of shaft l2. Consequently when the l5-mile-perhour train enters section 2, the relay CG will remain energized through contacts 38-39 for 100 seconds, and as this speed train requires seconds to reach the highway H after entering section 2, the highway warning will be displayed for 20 seconds prior to its arrival at the highway in the same manner as the previously considered high speed trains,

In the above cases it will be clear that the drum 28 operates in a clockwise direction while a train traverses section I to record the time required by trains at various speeds to reach the highway after entering section 2, and when the train enters section 2 the operation of drum 28 is reversed to delay the starting of the highway warning for a time which is effective to provide the required warning time. However, in the last assumed case of a lS-miIe-per-hour train, the starting of the Warning is delayed for 100 seconds, in which time, the 15-mile-per-hour train can traverse the entire 2,200 foot length of section 2. Consequently the starting of the highway warning cannot be further delayed by a train traveling at a slower rate of speed in the present organization, as the relay CG cannot be energized after a train enters the positive controlling section 3 as front contact I of relay T will then be opened.

In this manner, the present apparatus operates to provide a constant highway warning time of 20 seconds for all train speeds between 90 and 15 miles per hour, but due to the 440 foot length of section 3, the warning time is slightly increased by abnormally slow train movements below 15 miles per hour. However, it is to be understood that the assumed length of section 3 is merely an arbitrary value, and this length could be reduced to permit the system to include lower speeds in the range of operation of the time controlling mechanism.

After any of the above assumed train movements are completed through sections 2 and 3,

the timing apparatus is restored to its normal starting position by operation of the motor M over circuits completed by the restoring drums 26 and 21. When a train departs from section 2, it will be clear that the shaft l2 will ordinarily be operated in a counter clockwise direction from its normal position, this being caused by the fact that, due to the length of a train, track relay T is dropped for a period of time greater than the time required by the train to traverse section I, which latter time is not affected by the length of the train.

Consequently when the track relays T and '1 pick up, a restoring circuit is completed supplying current to motor M' in a normal direction, which circuit may be traced from the terminal of battery BY, through motor M, front contact 45 of relay T front contact 46 of relay T contacts 3l32 closed by sector 30, and back to the terminal of battery BY. The above normal direction of current in motor M operates shaft l2 in a clockwise direction until a normal position is restored and the circuit broken by sector'30 assuming its illustrated position which opens contacts 3l32.

However, in some instances the shaft 12 may be rotated in a clockwise direction from its illustrated position when track relays T and T pick up, such as may occur for example when a train movement is made in a reverse direction or when a train enters section I and then backs out without traversing section 2. In such a case the drum 2'! is effective to restore the shaft I2 to its normal position over a circuit providing current in a reverse direction through motor M, which circuit may be traced from the terminal of battery BX, through contacts 35-35 connected by sector 34, front contact 49 of relay T front contact 48 of relay T through the motor M, and back to the terminal of battery .BX. This reverse directi nof current in motor tinue through section 2.

-zM operates shaft 12 in a counter clockwise direction until a normal position is restored and the circuit broken by sector 34 assuming its normal position which opens contacts 3536.

In the previous description of train movements,

1 the trains were considered to continue past, the

highway H after traversing section I, but in some instances trains may stop in section 2 for making switching movements or the like, and in this case I arrangement however, the contacts ill-4| are provided in combination with relay for preventing continued operation of the highwaywarning during the entire time in which a train may remain, in section 2.

In other words, the same timing apparatus which is employed to measure the delay in starting the highway warning when a train enters section 2 is herein employed to measure off a period of time after which the warning may be discontinued in the event a train does not con- The cutout relay 0 is energized each time the shaft [2 is operated in ,a clockwise direction from itsnorm-al position over a circuit from the terminal of battery BX, through contacts 353B connected by sector 34, through the windings of relay 0, and back to the terminal of batteryBX. The relay 9 is maintained energized as long as section 2 is occupied over a stick circuit from the o terminal of battery BX, back contact 52 of .mal illustrated position, and after a predetermined time, the upper contacts 40-4l will be shunted by the upper endof sector 31 thereby closing a circuit which again energizes the control relay CG from contacts 404| shunted by sector 31, front contact 55 of relay ll, front contact 1 of relay T through the windings of relay CG, to

In this'm-anner, a train stopping in section 2 causes operation of drum 28 in a counter clockwise direction beyond its normal illustrated position, and after a predetermined period of time which may be adjusted according to the spacing of contacts 40 and 45, the highway warning is discontinued by the energization of relay CG. When the train again starts toward the highway, it will of course be traveling at a slow rate of speed, and consequently upon entering section 3,

the highway warning will again be started, and due to its slow rate of speed through section 3, thewarning will be given for at least the required time of 20 seconds.

A highway crossing signal controlling means has thus been provided, wherein a timing device is power operated in one direction during the time required by a train to traverse a first or timing section, and when the train enters a second or time controlling section, this timing device is power operated in a reverse direction to delay starting of the highway warning for that portion of the total time required by each normal train movement to reach the highway which is in excess of the predetermined warning time.

In this manner, all normal train movements to- Ward the highway result in a constant warning time, while abnormally slow trains start the warning at a fixed point by entering a third or positive controlling section adjacent the highway.

In the above operation of the timing device, it will be clear that in the event the device fails to continuously operate in a reverse direction during the occupancy of the second track section, the opening of the energizing circuit of the control relay CG at contacts 3839 would be delayed or possibly prevented until section 3 was occupied. Consequently in order to prevent a warning for a dangerously short period of time due to such a failure of the device to operate, the centrifugal contact means 20 has been provided in the circuit holding off the initiation of the highway warning, whereby the control relay CG is immediately deenergized to start the warning in the event the device stops or its speed is materially reduced.

The present arrangement further utilizes the same timing device to discontinue the warning in the event a train stops before reaching the highway by operating the timing device in a reverse direction a certain distance beyond its normal starting point, which distance constitutes a time interval after which it is considered safe to discontinue the warning in the event the train has not entered the positive controlling section 3. The positive controlling section 3 then provides a means for again starting the warning when the train subsequently starts and proceeds to cross the highway.

In the specific arrangement of the above means for discontinuing the warning in the event a train stops in controlling section 2, the contacts 40- are closed by the sector 31, and if after departure of the train from section 3 the drum 28 due to some abnormal condition is not properly restored. to its normal starting position, it will be clear that the energizing circuit for relay CG would be closed at contacts 4ll4l. Consequently in order to prevent an inadequate warning to result from the withholding of the warning until a subsequent high speed train had entered section 3, the cutout relay 9 has been provided. This relay is dropped when a train departs from section 2 to open the circuit through contacts 451-4! at its front contact 55 thereby preventing improper energization of control relay CG in the event the device fails to properly open contacts 40-.

The above rather specific description of one form of the present invention is given solely by way of example, and is not intended, in any manner whatsover, in a limiting sense. It is to be understood that various modifications, adaptations and alterations may be applied to meet the requirements of practice, without in any manner departing from the spirit or scope of the invention, except as limited by the appended claims.

What we claim is:-- i

1. In a signaling system for highway crossings on railroads, in combination, a portion of railway track intersected by a highway and divided into track sections traversed successively by trains approaching the highway, a time measuring device having a normal starting position, means operating the device in one direction while a train traverses a first of the track sections and operating it in the other direction while a train occupies a second of the track sections, a highway signal,

means energizing the signal upon occupancy of the second track section unless otherwise prevented, circuit means for the signal so governed by-the device upon movement in said one direction beyond a given pointas to prevent energization of the signal and so, governed by the device upon movement in the other direction beyond the given point as to energize the signaL'and circuit means so controlled by the device upon moving in the other direction to a point beyond the normal starting position as to deenergize the signal.

2. In a signaling system for highway crossings on railroads, in combination, a portion'of railway track intersected by a highway and divided into track sections traversed successively by trains approaching the highway, a time measuring device having a normal starting position, means operating the device in one direction while a train traverses a first of the track sections and operating it in the other direction while a train occupies a second of the track sections, a highway signal, means energizing the signal upon occupancy-of the second track section unless otherwise prevented, means for the signal so governed by the device upon movementin said one direction beyond a given point as to prevent energization of the signal and so governed by the device upon movement in the other direction beyond the given point as to energize the signaL'and means so controlled by the device upon moving in the other direction to a point beyond the normal startin position as to deenergize the signal. I v

3. In combination, a portion of railway trackintersected by a highway and dividedinto threetrack sections traversed successively by a train ap pro-aching the highway, a signal for the intersection, means for operating the signal when the second or third sections are occupied, a time measuring device having anormal starting position, means for operating the device in one direction while a train traverses the first track sec-- tion, and for operating it in the other direction while the second section is occupied, circuit means so controlled by movement of the device in said one direction to a given point as toprevent the energization of the signal due to occupancy of the second section, and so controlled by movement of the device in the other direction beyond the given point as toenergize the signal, and cut out means so controlled by movement of the device in the other direction to a point beyond the starting point as to discontinue operation of the signal during occupancy of the second track section. I

4. In combination, a portion of railway track intersected by a highway and divided into three vent the energization of the signal due to occupancy of the second section, and so controlled by movement of the device in'the other direction beyond the given point as to energize the signal, cut out means so controlled by movement of the device in the other direction to a point beyond the starting point as to discontinue operation of the signal during occupancy of the second track section, restoring means operable to return the time measuring device to said normal starting point when the first and second sections are unoccupied by a train, and means rendering the cutout means inefiective to prevent operation of the signal when the second section is unoccupied.

5. In combination, a portion of railway track intersected by a highway and divided into three track sections traversed successively by a train approaching the highway, a signal for the intersection, means for operating the signal when the second or third sections are occupied, a time measuring device having a normal starting position, means for operating the device in one direction while a train traverses the first track section, and for operating it in the other direction while the second section is occupied, circuit means so controlled by movement of the device in said one direction to a given point as to prevent the energization of the signal due to occupancy of the second section, and so controlled by movement of the device in the other direction beyond the given point as to energize the signal, cutout means so controlled by movement of the device in the other direction to a point beyond the starting point as to discontinue operation of the signal during occupancy of the second tracksection, the signal being invariably operated during occupancy of the third track section, and centrifugal means for causing immediate energization of the signal if the timing device fails in its movement in said other direction.

6. In combination, a portion of railway track intersected by a highway, a highway signal, an energizing circuit for the signal, a control device, means for operating the device in one direction in accordance with the speed of a train approaching the highway over a part of the track, and for operating the device in the other direction while the train is in a following part of the track, contacts controlled as the device moves in said one direction to open the signal circuit, and controlled as the device moves in said other direction to close the signal circuit, and contacts controlled by the device upon further movement in said other direction, to open the signal circuit.

OSCAR S. FIELD. JOSEPH E. WILLING. 

